Safari 3.. when i hit backspace is goes back

[ChrisMACosx]

when im in a text input box such as google search and i say for example make a mistake, but when i hit delete (backspace) to delete the mistake it goes back like when you hit the back button in the browser. can someone please help me fix this. also when i hit the spacebar it sometimes goes to the bottom on the page. I would be very grateful if anyone could help me.